Tom, let me be direct without being disrespectful What I modelled was a boom
length of 7ft for 20 metres and it is an abnormal yagi design which does not
fit what you are offering. I do not believe that NEC programs vary too much
on standard forms but when using tightly clustered elements on a short boom
lots of other things come in to play, and one has to be sure that the
program is all encompassing as designed to handle ALL abnormalities.
Obviously what you have offerred has serious problems on short yagi's let
alone abnormal design yagi's. It is my belief that because an element
reradiates
a portion of the RF that it received, extra elements that are closely
clustered can provide increased gain. Yes. my model
confirmed that but I was hoping that experts could point to a mathematical
analysis of max gain per unit length that was exacting in gain provided and
not "close enough" and not marred by other things that can occur by
measuring in the field.
It would appear from the responses that efforts in this area has not been
undertaken and which I will have to live with that.
But I do thank you for your offering
Art

"Tom Ring" wrote in message
. ..
wrote:

Tom, where is the link that goes with this info? It doesn't mean
anything as
it stands
Art


What? Of course it means something. It's an equation along with the
constraints.

Run any current decent 1 wavelength, or longer, yagi in your favorite
modeling program, and it will tell you whether you are near the gain you
should get for a well behaved yagi. Or it might tell you the model
isn't very accurate. It works well to test known designs against
unknown quality programs without having the known good modeling program
or test range.

If you want the database it was derived from, that might be arranged,
but it is in from a database program that Microsoft Office won't read,
so you might be out of luck there.

tom
K0TAR